1 /*
2 * Copyright (C) 2013 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "VoldUtil.h"
18 #include "Utils.h"
19
20 #include <libdm/dm.h>
21
22 #include <android-base/file.h>
23 #include <android-base/logging.h>
24 #include <android-base/stringprintf.h>
25 #include <android-base/strings.h>
26
27 using android::base::Basename;
28 using android::base::Realpath;
29 using namespace android::dm;
30
31 android::fs_mgr::Fstab fstab_default;
32
GetUfsHostControllerSysfsPathOnce()33 static std::string GetUfsHostControllerSysfsPathOnce() {
34 android::fs_mgr::FstabEntry* entry =
35 android::fs_mgr::GetEntryForMountPoint(&fstab_default, DATA_MNT_POINT);
36 if (entry == nullptr) {
37 LOG(ERROR) << "No mount point entry for " << DATA_MNT_POINT;
38 return "";
39 }
40
41 // Handle symlinks.
42 std::string real_path;
43 if (!Realpath(entry->blk_device, &real_path)) {
44 real_path = entry->blk_device;
45 }
46
47 // Handle logical volumes.
48 android::dm::DeviceMapper& dm = android::dm::DeviceMapper::Instance();
49 for (;;) {
50 std::optional<std::string> parent = dm.GetParentBlockDeviceByPath(real_path);
51 if (!parent.has_value()) break;
52 real_path = *parent;
53 }
54
55 std::string path = "/sys/class/block/" + Basename(real_path);
56
57 // Walk up the sysfs directory tree from the partition (e.g, /sys/class/block/sda34)
58 // or from the disk (e.g., /sys/class/block/sda) to reach the UFS host controller's directory
59 // (e.g., /sys/class/block/sda34/../device/../../.. --> /sys/devices/platform/00000000.ufs).
60 if (android::vold::pathExists(path + "/../device")) {
61 path += "/../device/../../..";
62 } else if (android::vold::pathExists(path + "/device")) {
63 path += "/device/../../..";
64 } else {
65 LOG(WARNING) << "Failed to get sysfs_path for user data partition";
66 return "";
67 }
68
69 // Verify the block device is UFS by checking for the presence of "uic_link_state",
70 // which is UFS interconnect layer link state.
71 // If not UFS, return an empty path.
72 if (!android::vold::pathExists(path + "/uic_link_state")) {
73 LOG(ERROR) << "The block device (" << Basename(real_path) << ") of " << DATA_MNT_POINT
74 << " is not UFS.";
75 return "";
76 }
77
78 LOG(DEBUG) << "The sysfs directory for the ufs host controller is found at " << path;
79 return path;
80 }
81
82 // get sysfs directory for the ufs host controller containing userdata
83 // returns an empty string on failures.
GetUfsHostControllerSysfsPath()84 std::string GetUfsHostControllerSysfsPath() {
85 static std::string ufshc_sysfs_path = GetUfsHostControllerSysfsPathOnce();
86 return ufshc_sysfs_path;
87 }
88